【译】第40节---EF6-命令监听
原文:http://www.entityframeworktutorial.net/entityframework6/database-command-interception.aspx
本节,将学习如何在执行数据库命令时拦截EF。
EF 6提供了在对数据库执行ExecuteNonQuery,ExecuteScalar,ExecuteReader操作之前和之后使用IDbCommandInterceptor拦截上下文的能力。
首先,实现IDbCommandInterceptor,如下所示:
class EFCommandInterceptor: IDbCommandInterceptor { public void NonQueryExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { LogInfo("NonQueryExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void NonQueryExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { LogInfo("NonQueryExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ReaderExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContextt<System.Data.Common.DbDataReader> interceptionContext) { LogInfo("ReaderExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ReaderExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext) { LogInfo("ReaderExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ScalarExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { LogInfo("ScalarExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ScalarExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { LogInfo("ScalarExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } private void LogInfo(string command, string commandText) { Console.WriteLine("Intercepted on: {0} :- {1} ", command, commandText); } }
可以在上面的代码中看到,IDbCommandInterceptor提供了六种执行方法。
现在,需要使用配置文件或基于代码的配置来配置拦截器。
配置文件:
<entityFramework> <interceptors> <interceptor type="EF6DBFirstTutorials.EFCommandInterceptor, EF6DBFirstTutorials"> </interceptor> </interceptors> </entityFramework>
基于代码配置:
public class FE6CodeConfig : DbConfiguration { public FE6CodeConfig() { this.AddInterceptor(new EFCommandInterceptor()); } }
所以现在我们可以在DbContext执行ExecuteNonQuery,ExecuteScalar和ExecuteReader时记录命令。